One decoded 5-byte child block of a conversation index.
date is the recovered absolute composition time of the reply.
random is the raw 8-bit uniqueness field (legacy MAPI documentation
splits it into a 4-bit random number and a 4-bit sequence count).
Summary
Types
@type t() :: %ThreadIndex.Reply{date: DateTime.t(), delta_code: 0 | 1, random: 0..255}